Problems with Vertex Tool (Invalid Solids)

[Illius]

[FIXED]

So I am working on my first map ever and tried to make use of the Vertex Tool to have an oddly shaped bridge. Thing is, I keep getting that it's an invalid solid and Hammer attempts to auto-correct it, causing this:
http://steamcommunity.com/sharedfiles/filedetails/?id=655140343

The bridge piece should be flush there but no matter what I do it either shrinks that size (which doesn't work for what I need) or enlarges the far side (which also doesn't work for what I need). How could I fix this as well as avoid it in the future? (And sorry if I am not providing something, I'm new to the forums due to this being my first true map made. Let me know what else needs to be provided).

 

[theatreTECHIE]

There are a few things you need to keep in mind when using the vertex tool:
1. All faces must be flat (ie all points that make up a face must be on the same plane) - The easiest thing to do here is make sure to move a whole side at a time, that way all faces usually stay flat. (NOTE: I said usually)
2. Brushes must be convex (ie no L or C shaped brushes can exist) - If you want a convex shape, make it out of multiple brushes, each of which are convex
3. If you stuff up a brush, it's usually easiest to delete it and make it again from scratch.

From your image, I'd say that you have a concave shape. Just remake this with two (or more) other brushes.

 

[Tumby]

1. All faces must be flat (ie all points that make up a face must be on the same plane) - The easiest thing to do here is make sure to move a whole side at a time, that way all faces usually stay flat. (NOTE: I said usually)

To be precise, moving an edge only works if the same face has another edge that is parallel to the one you are moving, and the face has 4 sides. 5 or more sided faces will always require a bunch of things to be moved in different ways.

From the image, it looks like this:

The red line is the one that has been moved up.

We can clearly see in the front (top left) view that this solid has a surface (orange) that is non-planar and is therefor invalid. To fix this, we split it into 2:

By splitting the brush through the middle, the orange plane is no longer a single plane, but rather two seperate planes. Because they are both triangles, they can not be invalid. It is important that we split the entire brush, and not just the face. If we only split the face, the brush will be concave, and therefore invalid again. If we wanted to only split the top face, we would have to split it like this:

Edit: Updated an image (forgot a line)

 

[Illius]

And that fixed it! Just had to divide it up along 2 main corners (I thought I already did that, but it's already such an irregular shape, so I guess I had to do it with this specific one). Good to know for the future! Thanks!